Clad metal and process of producing the same.



UNITED STATES PATENT oEEToE.'

JOHN F. MON NOT, OF NEW YORK, N. Y., ASSIlGrNOR TO DUPLEX METALS COM YORK, N.` Y, A`CORPORATION OF NEW YORK.

' CLAD METAL `am) PaocEss or PnoDUeme Tansania.-

Specification of Letters Ifatent.

A:mamita Aug. a, 1909.

Application led July 13, 1908. Serial No. 448,298;

To all whom it may concern: Y

f Be it known that I, JOHN F. MoNNoT, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented a certain new and useful Clad Metal and Process of Producing the Same; and I do hereby declare the following to be a full, clear, and exact description of the same, such as will enable others skilled lin the art to which it appertains to make and use the same.

This invention relates to clad metals and processes of producing same, .and comprises compound metal articles comprising a base of ferrous metal carrying a welded-on la er of an unlike metal permanently and indissolubly united thereto, and also a process of producing such clad metals, all as more fully hereinafter set forth and as claimed.

In various prior atents and patent applications I have set orth processes of uniting unlike metals, such as copper, silver, etc. to

bodies of ferrous metal, involving the contacting of very highly heated molten copper, silver etc. with a perfectly clean surface of ferrous metal; and in applications Sr. Nos. 391,673 and 400,843 I haveV described processes involvingthe casting of the coating metal through a layer of molten wiping material and the contacting of the metal .so cast `with a clean surface of the ferrous base or with a -film-coating previously formed on such surface by contact thereof with supermolten copper or like metal; the molten wiping material freeing the molten metal poured through it of entrained :1nd occluded gases, oxid impurities, etc., and insuring tough, dense and homogeneous cast metal. In an application filed June 13, 1908, S1.No. 438,396, i have described a process involving the casting of molten ferrous metal against the surface of a body of coating metal, the surface of such body being protected from oxidation by a layer of` molten wiping material through which the ferrous metal is cast.

According to myhpresent process, both the metal to form the coating, and the metal to form the core or base of the clad metal ingot or like object to be produced, are cast PANY, OF NEWy into the same mold through molten* wiping material, the two metals bein held apart b a 1suitable metal separator, with which bot 1 cast metals will unl-te inseparabl the metal of this separator being prefera l thoughf notnecessarily, substantially the same as one of the metalsoso cast; its surface bein protected against oxidation, or cleanedo prior to contact of the molten metal there-y with, by a suitable layer of molten wiping` material. or-other article will consist, therefore, of two layers of cast metal united to each other by being united to an intermediate substantial body of a metal which, even if identical in composition with one of :the cast metals and weld-united thereto, will customarily be distinguishable from such cast metal u on.

microscopic examination, owing to di erences of grain or structure, the result of prior working, whichdifferences are readily iscernible, to skilled metallurgical microscopists. The two cast metals may be cast simultaneously or one after the other; and by preference the metal of lower melting pointis cast last. Likewise in many cases means will be provided for cooling the mold rapidly once the metals have been cast rapid cooling tending to im rove the qualities of many metals, copper or instance. Heretofore this method of uniting unlike metals by casting them on opposite sides of a metallic separator has not been practicable, in the case of metals of high melting points or which oxidize readily and winch are required to be capable of being worked after casting; for it has been impracticable here tofore to avoid excessive internal flaws, blow-holes, etc., in one or both of the metals so cast, or to avoid such oxidation of the surface of the-separator as will prevent com- The resulting clad metal ingot` plete union of one or bothmetals thereto.

But the invention of the process of castingl the molten metal through a thick layer of wiping material, said wiping materialeither completely submerging the surface of solid metal to which the molten metal is to unite, or having marked oxid-dissolving power so that it progressively frees the surface of the solid metal of oxid just before contact of the molten metal with such surface, has overcome Vthis diiiiculty.'

In the accom anyin'g drawings-I illustrate, more or ess diagrammaticall the method of carrying out the said process, and apparatus such asmay be employed 1n car- 'rylng out'the process.

1 shows a cenlindrical mold, the cast. metal In 'said drawings-Figure tral vertical section of a c pouring tile, lseparator an odies cast according my said process; Fig.

2 shows a horizontal section on the. line of Fig. 1; Fig. 3 shows a top view of a mold'fr making rectangular ingots according to said process; F' ..4 a central vertical section thereof onthe ine y--y of Fig. 3; and Fio'. 5- shows a transverse section of a 'tue.

cylindrlcal mold indicating the use of a plus .per and like metals owing to the fact that,

according to this process, the metal need not be at the supermolten temperature, or

. mol s.

othery very high temperature, when cast; it bein vcommon to cast copper ingots in iron But in lieu of a metal mold, a mold of refractory material, for example, a mold of homogenized thermallyA conductive carbon, such as illustrated and describedin my application Sr. No. 430,097, may be used Such iron molds, and also carbon molds such as referred to, have the advantages that they withstand high temperatures and sudden great changes of temperature well, and are not disintegrated* by hightemperatures or by the action of ingredients of the wiping material which may be-used. If the copper or like lmetal were cast at supermolten temperature v'there might be some solvent action ofthe molten metal on theme'tal of an iron mold, though effective cooling of the mold by the means described would tend t prevent or greatly decrease such solvent action. At ordinary casting ltemperature lcopper has practically no action on'iron.

Suitable means, asv for example bands 3 and wedges 4, are provided to prevent separation of the sections of the mold duringv the casting and until the cast metal has solidified. A sectional mold is employed, instead of the one-piece mold commonly used in casting ingots,

in many cases that the ingot produced" shall simply because it iszdesirable-4 aaaesv have Ano draft vertically; otherwise a onepiece mold would be used. 5 designates the se arator, which in thisA case is a thin steel At its lower end this separator seats in a recess in the bottom of the mold, as illustrated in Fig. 4. Q6 is a suitable pouring tile Or'unneLand may be of refractory material, such as firel clay, or carbon, or may be of metal. It is provided with a central space 7 for the introduction of the molten metal lfor the coreandwith side spaces 8 for the introductionof the molten coating metal.

In carrying out the process, the mold having been assembled, and the separatorl put' in place, molten wiping material is introduced both 1ns1de and outside the separator; or a fusible solid wiping material may be placed in the mold instead, as the first ofthe molten'metal introduced will melt this solid wiping material. Borax, or a mixture of borax and sodium or potassium silicate, is a suitable wipin material. The pouring funnel 6 is put 1n p ace either before or after the addition of the wipin material,' as preferred. The. moltenl meta s for the core or base` and for the coating are then poured in; and in passing through the molten wiping material the molten metals are wiped or washed'and freed of entrained and occluded gases, oxid impurities, etc. and the metal, when solidiied, is free from blowholes, blebs, etc. The Amolten-wiping material may be introduced in such quantity as to completely1 submerge the separator, in whichcase it is notnecessary that the wip- Iing material shall contain much oxid-dissolving constituent; or, and preferably, the wiping material is used merely in such quanwhich the molten metal passes, the wiping material thencontaining a considerable proportion of oxid-dissolvlng constituent, `such as borax, which progressively cleans the surface of vthe separator as it rises. 'In general the moltensteel will be poured in in such quantity that it will completely fill j the interior of the. separator and will rise some- I what into they funnel 6, the metal within the funnel solidiying last, owing to there being lesscooling action 'at the top, particularly? if the funnel is of material 'of -low heat 'conductivity-re clay or carborn for example; the molten steel in the upper portion of the separator-and in the funnel serving to fill up any pipes and the like formed in the solidication'of the metal below, so insuring *a good quality of the cast metal. The wiping material, being of low thermal conductivity, acts to delay somewhat the solidicationlof this upper layer of molten metal and thereby aids in obviating piping. The fluid pressure due to this additional height of metalalso helps to insure sound dense metal free' from pipmgfand the like.

tity thatit will form a deep layer through cames? In a broad sense, it is immaterial which of the two metals is poured first, or Whether both are poured simultaneously; but in gen-l eral it is best to pour the steel lirsthand then to pour-the copper or other coating metal (they casting temperature of which is much lower than that of the steel); the coating metal then helping -to cool the `ste,el.` Soon-after the coating metal-is poured, in either case, cooling fluid or its equivalent will be passed through the cooling jacket of the mold, thereby hastening the solidication of the coating metal, preventing it from being heated, by conduction from the molten or partlysolidied steel, to such extent that the molten coating metal will attack the mold, causing the coating to shrink on tothe separator and so causing the separator to contract with the cast steel within it and .preventing shrinking of the cast steel away from the separator before a complete union between the se arator and cast steel has been formed, an insuring a good quality of coating; for as previously stated, copper and many other metals are improved in quality by being caused to solidify quickly.

As explained in my Patent No. 853,716, and in other patents and pending applications, copper cast at ordinary castingI tem` perature against the surface of a solid relatively cool steel object does not form a weldunion with the steel, but does form such a union with the steel .if` contacted therewith at a higher or supermolten temperature. ln the invention ofthe present case it is probable 'that the coating metal in immediate proximity to the separator is raised to supermolten condition by conduction of' heat from the molten steel; for which reason it is unnecessary and inadvisable to cast the coating metal at supermolten temperature. The chilling of the mold as described prevents t-he outer layers of the coating metal reaching the supermolten condition.

It will be observed'that since the cast c0ating metal contracts at the' same time as the cast steel core or base, and the steel separa tor contracts with both, there is no tendency for separation of the one metal from the other;A and owing to the temperature to which the separator -and the layers of coating metal adjacent thereto are raised by the steel, complete union of both cast metals to the separator is insured.

In general the surfaces of the separator will be thoroughly cleaned, by Sandblasting or otherwise, before said separator is introduced into the mold; but the deep layers ofwiping material on both sides of the separator are capable of dissolving-a considerable amount of oxid on the surfaces of the separator.

Much the same method maybe usedjin producing rectangular ingots. Figs. 3 and 4 illustrate the formation of such ingots7 coated on both sides. `In these figures, @designates a suitable rectan ular mold, and l0, 10 separator plates therein, and 11 a suitable pouring funnel or tile. In performing the process, molten steel. or other sultable'm-etal is poured, through molten wiping material',

into the space between these separator plates, v

and molten coating metal into the spaces between these sep'arator'plates and the sides of the mold. The operations which take place are substantially the same as n the formation of round ingots as previously described...

It will be understood that/the process above described is applicable for the making of a variety of ingots of different forms, either round, square, rectangular, hollow, or of other shapes; that in the case of a hollow object to be coated, the coating metal may be introduced on the inside instead of the outside; etc. The necessary modifications in the form and constructionof molds, separators, etc. .will'readily suggest themselves to those skilled in the art. Likewise it will be understood that either in the apparatus shownlin Figs. 1 and 2', or in the apparatus shown in Figs-3 and Il, the copper or like metal of lower melting point may be cast on the inside of the separator or separators and the steel or other metal of higher melting point may be caston'the. outside of the separator or separators. y,

In the union of high carbon steel and copper, some difficulty has been experienced owing to thetendency of the oxygen of the slight amount of copper oXid necessarily present in goed copper to insure a good` quality of metal, to combine with-the carbon of the steel. This diiiculty is overcome according to the present process because the `separator itself may be of -mild or low carbon steel,.while the steel cast therein' may be of high carbon A stl., Low carbon steel unites readily to highv carbon steel cast against it and copper containing a slight amount of copper oxid unites readily to low carbon steel.

I find it convenientin pouring the molten metals as hereindescribed, topour most but not quite all of the steel first, -then to pour the copper and linally toL pour the remainder of the steel; the steel last poured servf ing to fill any spaces left as a result of shrinkage etc., and to` lill in any pipes that may have formed.

When castingvery large steel cores or bases, in order to prevent the metal in the center Jfrom being less dense than at the outside,1 I may not only employ a separator to separate the steel from the copper, but may 4also employ avseparator to separate the steel into two or niore parts. This is illustrated in Fig. 5,; in which lzgdesignates a second,

separator. In such case molten steel is poured first into the space between separators 5 and 12, then the copper is poured and then steel is poured into the space Within separator 12. I

Preferably the ingots produced as above described, are rolled directly after being taken from the mold and Without reheating, or at most only after being subjected to more or less soaking lit-iat. This has they advantage that during rolling the steel core or base will be at a. higher temperature than the copper coating, both because of the steel having had a higher temperature initially and because of the greater `hcat conductivity of copper. It is thus possible to roll the ingot with the steel core or base at a temperature closel to or above" the meltingpoint of copper-a telnperature at which the steel could 'not be rolled otherwise, and a teinperature at which the steel is much softer than if the limit of the temperature were set by the temperature to which copper can be heated for rolling.

Before introducing the molten metals into the -mold, I preferably heat the moldA and separator or separators. To this end the mold may have in its bottom an opening 13 through Which the flame from a suitable burner may be projected into the mold; this opening being closed by a suitable plug 14 of clay or the like before the molten metal is introduced. i

In another application Serial No. 443,299, filed July 13, 1908 which' I am about to file, I have described a process of forming compound bodies of like metals comprising the casting of molten metal through a deep layer of wiping material into 4contact with the surface of a solid body of like metal and the progressive cleansing of such surface by the action of the wiping material asI itis displaced and rises, and in such application claim broadly the progressive cleansing of a surface against which molten metal is cast by the action of material displaced by the molten metal. Therefore I.doy not claim such invention broadly herein.

When the ingot mold employed is Very thick, in proportion to the thickness of the bodies of molten metals, and is of thermallyconductive material, it will in general have in itself sulticient heat-storage and heat-abstracting capacity to render .the use of spe- 'cial cooling means unnecessary; or instead of employing a cooling jacket the mold may in many cases be cooled sufficiently by flowing Water or other cooling Huid against its outer surface.

In some cases the separator may be of a non-ferrous metal. For example, in the case of a copper steel article," the separator may be of copper. This may be especially desirable when electrical conductivity wire and the like is to be produced, the copper separator, although probably melted by the steel, preventing the wandering of portions of the steel into the main portion of the copper. Where the separator is of metal ofl lower melting point than thev steel, in general the cooling of the ingot mold will have to be particularly efficient.

What Il claim is 1. 'A process of producing clad metal objects comprising unlike metals Weld-united,

which .foinjnisesl casting molten bodies of unlike metals into contact with opposite surfaces of a separator of material capable of welll-uniting with both the metals so cast, and progressiwij/,cleaning one or both said surfaces by the action thereon of a deeper layer of (.fleausing material progressively displaced by the molten metals so cast.

2. A process of producing clad metal objects comprising unlike metals Weld-united, which comprises `casting molten bodies of unlike metals into contact with opposite surfaces of a separator of material capable of Weld-uniting with both the metals so cast, and progressively Acleaning one or bothv said surfaces by the action thereon of a deep layer of molten flux containing oxiddissolving material. i

3. A process oli-producing clad metal objects comprising unlike metals weld-united, which comprises casting molten bodies of unlike metals into Contact' with opposite surfaces of av separator ofmaterial capable of Weld-uniting with both of the metals so cast, one or both of the metals so cast being cast through a deep layer of wiping material in contact with the corresponding ,surface of said separator and comprising materialhaving a cleansing action on said separator.

4:. A process ofproducing clad metal objects comprising i1nlike1met`als Weld-united, which comprises casting molten bodies of unlike metals into contact with oppositesurfaces of a separator-of material capable of weld-uniting with both of the metals so cast, one or both of the metals so cast being cast through a deep layer of molten inorganic wiping material in contact with the corresponding surface of said separator and comprising oxid-dissolving material.

5. A process of producing clad metal obl by one or both of the molten metals so cast.

6. A process of producing clad metal objects comprising unlike metals weld-united, which comprises casting molten bodies of unlike metals into contact Wlth opposite sur-y faces of a separator of material capable of weld-uniting with both said (metals so cast, one or' both of said metals being cast through a deep layer of wiping material, and progressively cleaning one or both said surfaces of said separator by the action of a deep layer of molten fluxA containing oxid-'dissolving material.

7. A process of producing cladv met-al objects comprising unlike metals weld-united, .which comprises casting molten bodies. of ferrous and non-ferrous metals intocontact with opposite surfaces of a ferrous metal separator, and'l progressively cleaning one or both. said surfaces by the action thereon of a deep layer of cleansing material progressively displaced by the molten metals so cast.

8. A process of producing clad metal objects comprising unlike metals weld-united, which comprises casting molten bodies of ferrous and non-ferrous metals into contact with opposite surfaces of a ferrous metal separator, and progressively cleaning one or both said 'surfaces by the action thereon of a deep layer of molten fiuxcontaining oXiddissolving material. i

9. A process of producing clad met-al objects comprising unlike metals weld-united, which comprises casting molten bodies of ferrous and non-ferrous metals into contact separator, one or both of the metals so cast being cast through a deep layer of molten inorganic wiping material in contact with the corresponding surface of said separator, said wiping material comprising oXid-dissolving material.

1l. A process of producing clad metal objects comprising unlike metals weld-united, which comprises casting molten bodies of ferrous and non-ferrous, metals into contact with opposite vsurfaces of a ferrous metal separator, and progressively cleaning one or both said surfacesV of said separator by the action thereon of fusible mineral cleansing material progressively displaced by one or both of the molten metals so cast.

12. A process of producing clad metal objects comprising unlike metals weld-united,

which comprises casting molten bodies of 'steel'and copper into contact with opposite .surfaces of a steel separator, and progresslvely cleaning one or both said surfaces by the actionthereon of a deep layer of cleansmg material progressively displaced by the molten metals so cast.

14. A- process of producing clad metal objects comprising unlike metals weld-united, which comprises casting molten bodies of steel and copper into contact with opposite surfaces yof a steel separator, and progressively cleaning one or both said surfaces by the action thereon of a deep layer of molten flux containingoXid-dissolving material."

15. A process of producing clad metal objects comprising unlike metals weld-united, which comprises casting molten bodies of steel and copper into contact with opposite surfaces of a steel separator, one or both of the metals so cast being cast through a deep layer of wiping material in contact with the corresponding surface of said separator and 17. A process of producing clad metal ob-V jects comprising unlike metals Weld-united, which comprises casting molten bodies of steel and copper into contact with opposite surfaces of a steel separator, and-progressively cleaning one or both said surfaces of said separator by the action thereon offusible mineral cleansing material progressively displaced by one or both of the molten metals so cast.

18. A process of producing clad metal objects comprising unlike metals Weldunited, which comprises lcasting molten bodies of steel and copperv into contact with opposite surfaces of a steel separator, and progressively cleaning one or both said surfaces of said separator by the action of a deep layer ofmolten flux containing oXiddissolving material.

19. A process of producing clad metal objects comprising unlike metals of different inciting points weld-united, which comprises casting molten bodies of said unlike metals on opposite sides of a separator of material capaoie of weld-uniting with b otlivmetals so cast and abstracting heat from the metal of lower melting point, and thereby iiiailitaiiiing thc temperature of a portion thereof below the temperature of the other metal.

:20. A process of producing clad metal objects comprisingunlike mel-als of dillerent melting points weld-united, which comprises casting molten bodies of said unlike metals on opposite sides of a separator of material capable of weld-uniting with both metals so cast', the metalof lower melting point being also cast against a heat-abstracting body, and by the action of said heat-abstractiilg body maintaining the temperature of the portion ofthe molten metal adjacent thereto materially below the temperature ofthe other metal.

2l. A process of producing clad metal objects comprising unlike metais of different melting points weld-united, which coinprises casting molten bodies of said unlike metals on opposite sides of a 'separator of material capable of \'veld-unitiiig with both metals so cast, the iiietalof lower melting point being also cast against the surface of a jaeketeo mold, and passing cooling medium into the jacket of said mold and thereby maintaining the temperature of the-portion of the inolteninetal adjacent to said mold materially below the temperature of the other metal. 1

22. A process of producing clad metal object-s comprising-ferrous metal and nonferi'ons metal of lower melting point than said ferrous metal, which comprises casting molten bodies of said ferrous and non-ferrous metals on opposite sides of a separator of material capable of weld-uniting to both, and abstracting heat from the non-ferrous metal and thereby maintaining the temperature of a portion thereof below the temperature of the ferrous metal.

:23. A process Aof producing clad metal objectscomprising ferrous metal and nonferrous metal of lower melting point than' said ferrous metal, which comprises casting molten bodies of said ferrous and non-ferrous inetalson opposite sides of a separator of material capable of weld-uiiiting to both, the non-ferrous metal being also castl against a heat-abstracting body, and by the action of said heat-abstracting body maintaining the temperature of the portion of the molten metal adjacent thereto materially below the temperature of the ferrous metal.

24. A process of reducing clad metal objects comprising, errous metal'and non` ferrous metal of lower melting point than said ferrous metal, which comprises casting molten bodies of said ferrous and non-ferrous metals on opposite sides of a separaagainst the surface of a jacketed mold, aiid l passing cooling medium into the jacket of said mold and thereby maintaining' the teniperature of the portion of the molten metal adjacent to said mold materially below thel temperature of the ferrous metal.

25. A process of producing clad `metal objects comprising steel and copper, which comprises casting molten bodies of said steel and copper on opposite sides of a separator of material capable of weld-uniting to both, and abstracting heat from the copper and thereby maintaining the temperature of a portion thereof below the ten'iperatnre of the steel.

2o. A process oil' producing clad metal objects comprising steel and copper, which comprises casting molten bodies of said steel and copper on opposite sides of a separator of material capable of weld-uniting to both, the copper being also cast against a heatabstracting-body, and by the action of said heat-abstracting body maintaining the temperature of the portion of the molten metal adjacentthereto materially below the teniieratui'e of the Steel.

27. A process of producing clad metal objects comprising steel and copper, which comprises casting molten bodies of said steel and copper on opposite sides of a separator of material capable of weld-uniting to both, the copper being also cast against the surface of a jacketed mold, and passing cooling mold materially below the temperature of the steel.

28. A process of producing clad metal objects comprising unlike metals of different melting points Weld-united, which comprises casting the lmetals of higher and lower melting points on the inside and outside respectively, of a tubular separator of material capable of weld-uniting to both, the metal of lower' melting point being cast last and by its chilling action and its contraction causing the separator to contract with the metal within it.

29. A process of producing clad metal objects comprising unlike metals of different melting points weld-united, which comprises casting the metals of higher and lower melting points on the inside and outside, respectively, of a tubular separator of material capable of weld-uniting to both, said separator contained within a mold adapted to abstract heat from the metal of lower melting point cast between the sides of said molti and said separator, and casting the metal of lower melting point last and by its chilling action and its contraction causing the separator to contract with the metal Within it, the heat-abstracting action of the separator limiting the temperature of the metal adjacent to it;

30. A compound metal object comprising layers of ferrous and non-ferrous metal, the latter a metal of high melting point, Weldunited by an intermediate layer of a metal like one of said metals and to which both are weld-united.

31. A compound metall object comprising 15 In testimony whereof I aix my signature,

two Witnesses. JOHN F. MONNOT.

Witnesses:

H. -M. MARBLE, FRANK E. RAFFMAN.

in the presence of 

